Landslides and debris flows caused by an extreme rainstorm on 21 July 2012 in mountains near Beijing, China

An increasing number of debris flows in mountainous regions near Beijing have been documented in the last few decades, some of which were triggered by extreme rainstorms. In this paper, we examine a total of 40 landslides and 16 debris flows triggered by an extreme rainstorm on 12 July 2012. Rainfall records were used to check the triggering conditions. Field reconnaissance and measurements, supported by aerial photo interpretation, were conducted to identify the distribution, mobility, and volume change of landslides. This extreme rainstorm provided a higher triggering condition than the required rainfall threshold in the study area. The rainfall intensity during periods of intense rainfall was comparable to some typhoon events and other extreme rainstorms. Records from seven rainfall stations reveal that the rainfall in valley floor areas was higher than that in mountainous and plain areas. The rainfall-induced landslides were small, and most of them were located in terrain with a slope gradient >25° and pelitic dolostone strata underneath. The watersheds have a small area, short stream length, and the debris flow volume is low because of the limited material resources. The landslide-type debris flows exhibit weak mobility as the debris flow deposits mainly consist of gravels. Although the material resources from shallow landslides are small, the debris flow volume is 1.03–4.05 times the initial landslide volume, indicating that the debris flow entrains sediments. Finally, the entrained sediments per channel length and debris flow volume magnification were positively related to the watershed area and channel length, respectively. Our findings proved that an extreme rainstorm can trigger landslides and debris flows in an area where no such hazards were documented before. It is necessary to identify the site prone to landslides and debris flows, which may pose a hidden threaten for local inhabitants.

[1]  Peng Cui,et al.  Experimental study on cascading landslide dam failures by upstream flows , 2013, Landslides.

[2]  Richard M. Iverson,et al.  Debris-flow mobilization from landslides , 1997 .

[3]  Wentao Yang,et al.  Rainfall intensity–duration threshold and erosion competence of debris flows in four areas affected by the 2008 Wenchuan earthquake , 2017 .

[4]  P. Allen,et al.  Sediment flux from a mountain belt derived by landslide mapping , 1997 .

[5]  Bruce D. Malamud,et al.  Self-Organized Criticality Applied to Natural Hazards , 1999 .

[6]  Kai-heng Hu,et al.  Comparison of debris-flow volume and activity under different formation conditions , 2013, Natural Hazards.

[7]  Kyoji Sassa,et al.  Pore-pressure generation and movement of rainfall-induced landslides: effects of grain size and fine-particle content , 2003 .

[8]  Yunqi Wang,et al.  Variation in initiation condition of debris flows in the mountain regions surrounding Beijing , 2016 .

[9]  N. Hovius,et al.  Supply and Removal of Sediment in a Landslide‐Dominated Mountain Belt: Central Range, Taiwan , 2000, The Journal of Geology.

[10]  Richard M. Iverson,et al.  Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment , 2011 .

[11]  Mario Parise,et al.  Wildfire impacts on the processes that generate debris flows in burned watersheds , 2012, Natural Hazards.

[12]  Scott McDougall,et al.  Entrainment of material by debris flows , 2005 .

[13]  J. E. Gartner,et al.  Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California , 2008 .

[14]  V. K. Dadhwal,et al.  Landslides triggered by the June 2013 extreme rainfall event in parts of Uttarakhand state, India , 2015, Landslides.

[15]  Alessandro Simoni,et al.  Experimental evidences and numerical modelling of debris flow initiated by channel runoff , 2005 .

[16]  P. Bartelt,et al.  Measurements of hillslope debris flow impact pressure on obstacles , 2012, Landslides.

[17]  P. Cui,et al.  Scale amplification of natural debris flows caused by cascading landslide dam failures , 2013 .

[18]  Chuan Tang,et al.  Catastrophic debris flows triggered by a 14 August 2010 rainfall at the epicenter of the Wenchuan earthquake , 2011 .

[19]  Bruce D. Malamud,et al.  Power-law correlations of landslide areas in central Italy , 2001 .

[20]  S. Cannon.  Debris-flow generation from recently burned watersheds , 2001 .

[21]  Kyoji Sassa,et al.  Downslope volume enlargement of a debris slide–debris flow in the 1999 Hiroshima, Japan, rainstorm , 2003 .

[22]  Richard M. Iverson,et al.  Landslide triggering by rain infiltration , 2000 .

[23]  Yoichiro Fujii.  Frequency Distribution of the Magnitude of the Landslides Caused by Heavy Rain-Fall , 1969 .

[24]  Jason W. Kean,et al.  In situ measurements of post‐fire debris flows in southern California: Comparisons of the timing and magnitude of 24 debris‐flow events with rainfall and soil moisture conditions , 2011 .

[25]  Sun Jianhua.  Multi-Scale Characteristics of Record Heavy Rainfall over Beijing Area on July 21, 2012 , 2013 .

[26]  C. Tsou,et al.  Catastrophic landslide induced by Typhoon Morakot, Shiaolin, Taiwan , 2011 .

[27]  N. Caine,et al.  The Rainfall Intensity - Duration Control of Shallow Landslides and Debris Flows , 1980 .

[28]  F. Wei,et al.  Real‐time measurement and preliminary analysis of debris‐flow impact force at Jiangjia Ravine, China , 2011 .

[29]  Chaojun Ouyang,et al.  Entrainment of bed material by Earth‐surface mass flows: Review and reformulation of depth‐integrated theory , 2015 .

[30]  Yong Li,et al.  Intensity-duration threshold of rainfall-triggered debris flows in the Wenchuan Earthquake affected area, China , 2016 .

[31]  Tjalling de Haas,et al.  Effects of debris flow composition on runout, depositional mechanisms, and deposit morphology in laboratory experiments , 2015 .

[32]  Jeffrey A. Coe,et al.  Forecasting inundation from debris flows that grow volumetrically during travel, with application to the Oregon Coast Range, USA , 2016 .

[33]  C. J. van Westen,et al.  Analysis of debris flow behavior with a one dimensional run-out model incorporating entrainment , 2012 .

[34]  Xiaoqing Chen,et al.  The 12 May Wenchuan earthquake-induced landslide lakes: distribution and preliminary risk evaluation , 2009 .

[35]  Richard M. Iverson,et al.  Elementary theory of bed‐sediment entrainment by debris flows and avalanches , 2012 .

[36]  J. L. Yeh,et al.  Hydrometeorological and landuse attributes of debris flows and debris floods during typhoon Toraji, July 29–30, 2001 in central Taiwan , 2005 .

[37]  Ying-Hsin Wu,et al.  Preliminary investigation of the 20 August 2014 debris flows triggered by a severe rainstorm in Hiroshima City, Japan , 2015, Geoenvironmental Disasters.

[38]  Marcel Hürlimann,et al.  Field and laboratory analysis of the runout characteristics of hillslope debris flows in Switzerland , 2015 .

[39]  Chjeng-Lun Shieh,et al.  Variability in rainfall threshold for debris flow after the Chi-Chi earthquake in central Taiwan, China , 2009 .

[40]  Martin Beniston,et al.  Rainfall characteristics for periglacial debris flows in the Swiss Alps: past incidences–potential future evolutions , 2011 .

[41]  Dawei Han,et al.  The processes and mechanism of failure and debris flow initiation for gravel soil with different clay content , 2010 .

[42]  T. de Haas,et al.  Effects of debris-flow composition and topography on runout distance, depositional mechanisms and deposit morphology. , 2015 .

[43]  L. Cascini,et al.  Spatial and temporal occurrence of rainfall-induced shallow landslides of flow type: A case of Sarno-Quindici, Italy , 2011 .

[44]  M. Jakob,et al.  Debris-flow Hazards and Related Phenomena , 2005 .

[45]  D. Petley,et al.  The impact of landslides and debris flows triggered by Typhoon Mindulle in Taiwan , 2005, Quarterly Journal of Engineering Geology and Hydrogeology.

[46]  Guang-qi Chen,et al.  Catastrophic debris flows on 13 August 2010 in the Qingping area, southwestern China: The combined effects of a strong earthquake and subsequent rainstorms , 2012 .

[47]  Christian Scheidl,et al.  Empirical prediction of debris‐flow mobility and deposition on fans , 2009 .

[48]  Cma Training.  Investigation of Beijing Extreme Flooding Event on 21 July 2012 , 2012 .

[49]  Ping-Sien Lin,et al.  Estimation of sediment volume of debris flow caused by extreme rainfall in Taiwan , 2011 .

[50]  J. W. Kean,et al.  Evolution of a natural debris flow: In situ measurements of flow dynamics, video imagery, and terrestrial laser scanning , 2010 .

[51]  Simon M. Mudd,et al.  The mobilization of debris flows from shallow landslides , 2006 .

[52]  Fu-Shu Jeng,et al.  Characteristics of hazards induced by extremely heavy rainfall in Central Taiwan — Typhoon Herb , 2000 .

[53]  Wang Jingy.  Analysis on Water Vapor Transport and Budget of the Severe Torrential Rain over Beijing Region on 21 July 2012 , 2014 .

[54]  Hsien-Ter Chou,et al.  Geomorphologic characteristics of catastrophic landslides during typhoon Morakot in the Kaoping Watershed, Taiwan , 2011 .